\\[-1.8ex] Soil Heterogeneity & $-$0.275 & $-$0.275 & $-$0.310$^{*}$ & $-$0.270 & $-$0.151 & $-$0.259$^{*}$ \\ 
  & (0.217) & (0.217) & (0.179) & (0.189) & (0.155) & (0.147) \\ 
\\[-1.8ex] 
Observations & 19,881 & 19,881 & 19,881 & 19,881 & 19,881 & 19,837 \\ 
R$^{2}$ & 0.001 & 0.001 & 0.207 & 0.235 & 0.253 & 0.268 \\ 
